While I understand government agencies' desires to investigate persons of interest, the checks and balances of the system were put in place to do just that – check and balance the power of the system. It's outrageous that agencies feel they can side-step these checks and leave out the need to get a judge's approval for these kinds of things.
A response from the Internet Archive (2016) also stated:
> The NSL we received includes incorrect and outdated information regarding the options available to a recipient of an NSL to challenge its gag. Specifically, the NSL states that such a challenge can only be issued once a year. But in 2015, Congress did away with that annual limitation and made it easier to challenge gag orders. The FBI has confirmed that the error was part of a standard NSL template and other providers received NSLs with the same significant error. We don’t know how many, but it is possibly in the thousands (according to the FBI, they sent out around 13,000 NSLs last year).
I wonder what kind of legal action could even be taken against this kind of treatment (being given wrong / outdated information on legal options)?